Line sets are the copper lines which connect an outdoor condensing unit/heat pump to an inside air handler or evaporator coil. Line sets are available in different lengths and diameters to fit most applications. Below are tips to help select the proper size to match the needs of your system.

1. When purchasing refrigeration lines, measure the length of line set needed to connect your outdoor condenser to the indoor forced air equipment. Based on that length, the correct size diameter line set can be selected which will ensure your system meets the listed SEER rating and capacity. Once you have accurately measured the length needed, use our chart below to find the diameter best for your system.

2. When feeding a new line set through the wall, it is typically easier to feed the lines “out” from the inside of the home rather than “in” from the outside. This will also minimize any damage to the suction line insulation when feeding it through the wall. It is always advisable to slowly roll the lines open to avoid putting crimps in the lines. If you encounter a tight radius bend, cut the suction line and braze a 90° or 45° fitting to avoid kinking the flexible tube. The installation DVD includes more tips on running line sets.

3. When sweating the line set to the equipment or fittings use an oxygen/acetylene torch (preferred since it is hottest) or MAPP gas torch and high silver content brazing rods to achieve a proper brazed connection. Propane gas or MAPP/PRO torches should *not* be used, since they will not generate enough heat to make a good connection. When brazing pipes into air conditioning condenser or heat pump, first tie a wet rag around the service valves to dissipate heat. If this isn't done, there are small rubber O-rings in the valves which can melt and cause refrigerant leaks. If you aren't familiar with using a torch, for your safety have your air conditioning contractor perform this task for you. Wear proper eye and hand protection when operating a torch.

4. Once all of the line set connections have been brazed, a vacuum must be pulled on the system to evacuate the lines. The manufacturer's installation instructions describe the system evacuation process. If your system operates on R-22, then by law you must have an HVAC technician do this part of the job for you.

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In 2002 Alpine Home Air Products became the first company to sell heating, air conditioning and indoor air-quality products online. We have proudly served hundreds of thousands of customers, helping them save time and money by buying their products direct.